Polk MM 6501 install question

Pat C.

Just wanted to get some feedback from people who've installed this series of speaker in a 370. Would be much easier for me to ask where you're installing the cross-overs "before" I begin the project. Also, am assuming that I'll be replacing the "top" OEM speaker with the 2 tweeters that come in this set? Just went out tonight and cut out some UHMW plates for the tweeters to sit in.
Am planning on using the Clarion or Kenwood 308 or CX 501 receiver in place of the non-Bose player.
Wish I had the extra dough to go with a higher quality unit, but for now, will have to stay with this plan....Comments, suggestions would be appreciated...
Pat
PS, should I worry about running new wire as long as I'm wiring for the crossovers? If so, what gauge?